Sgrew-propeller



(No Model.)

A. D. HALL & G. B. SLOAN.

SCREW PROPELLER. No. 887,229. Patented Aug. 7, 1888.

WIZ'JV I INVENTOR s, 8 v

, N. PETERS. Pholo-Lithogmpher, Washingion. u c.

UnirTn STATES PATENT Tries.

ALEXANDER D. HALL AND GEORGE B. SLOAN, OF SAN FRANCISCO, CALIFORNIA.

SCREW-PROPELLER.

SPECIFICATION forming part of Letters Patent No. 887,229, dated August'7, 1858.

Application filed April 3, 1888. Serial No. 269,640. (No model.)

To all whom it may concern:

Beit known that we, ALEXANDER D. HALL and GEORGE B. SLOAN, citizens ofthe United States,residing at San Francisco, in the county of SanFrancisco and State of California, have invented new and usefulImprovements in Screw-Propellers, of which the following is aspecification.

Our invention relates to an improvement in screwpropellers for vessels;and it consists in the peculiar construction and combination of devicesthat will be more fully set forth hereinafter, and particularly pointedout in the claims.

In the accompanying drawings, Figure 1 is a side elevation of ascrew-propeller embodying our improvements. Fig. 2 is an end elevationof the same. Fig. 3 is a detailed sectional view taken on the line 0c :rof Fig. 1. Fig. 4 is a similar view taken on the line 3 3 of Fig. 1.

Arepresents the propeller-shaft, which projects rearward from thedead-wood of the stern of the vessel for a suitable distance, and hasits bearings in the stern-post and in the rudderpost, in the usualmanner.

B represents the blade of the propeller, which is spiral in form andmakes one complete revolution on the propeller-shaft, so that thepropeller is perfectly balanced at all points and is caused to act upona column of water which is equal to the diameter of the propeller. Thepitch of the screw-blade may be varied to suit the requirements of thecase; but we have found by experiment that probably the best results areobtained when the length of the blade is somewhat in excess of thediameter of the propeller. The said blade is formed of a number ofsectors, 0, each of which is cast or wrought separately, and the saidsectors are provided at their inner ends with hubs D, which are keyedseparately to the shaft. The opposing edges of the sectors are providedwith tongues and grooves, and thereby perfectly tight joints are formedbetween the sectors, thereby making the surfaces of the propeller-bladeperfectly flush and entire through out the entire length and breadth ofthe blade, as will be readily understood.

E represents a spiral flange, which is arranged on the outer edge of thepropellerblade and at right angles thereto, the said flange beingdisposed in a plane which is parallel with the axis of the propeller.The said flange extends forward and rearward beyond the sides of thepropeller blade, and in practice the rearward-projecting portion of theflange is equal to about twice the width of the forward-projectingportion thereof. \Vhen the propeller is in operation, this flangeprevents the water from being thrown laterally and radially from thepropeller, and causes a column of Water which is equal to the diameterof the propeller to be forced directly aft in the wake of the vessel,thereby very materially increasing the power of the propeller andrendering the same much more serviceable.

\Ve have found in experimental test that with a propeller thusconstructed we were enabled to obtain twenty-five per cent. more powerand effect an economy of ten per cent. in the fuel over propellers ofthe ordinary construction.

The flange E is made in sections of suitable length and is adapted tobreak joints with the bladesections on the outer edges of the spiralblade, and said flange is provided onits inner side with a pair ofinwardly-extending radial flanges, F, thereby forming a groove betweenthe said flanges in which the outer ends of the blade-sections arefitted. Bolts G are passed through transverse aligned openings made inflanges F and in the outer ends of the bladesections, and serve tosecure the flange E firmly to the spiral blade. By reason of the saidflange E being arranged in a plane parallel with the axis of thepropeller said flange is enabled to slip through the water withoutexerting radial or centrifugal action thereon, and without in any mannerretarding the motion of the vessel. The front projecting portion of theflange E is of less width than the rear projecting portion thereof, soas to offer as little unnecessary resistance as possible to the rotationof the propeller when the vessel is advancing and at the same timeenable the said projecting portion of the flange to prevent the waterfrom being dispersed radially from the propeller when the latter isreversed, consequently enabling the vessel to be stopped or backed in avery short space.

Inasmuch as propellers thus constructed do not disperse the waterradially and force the same rearward in a solid column equal to thediameter of the propeller, the same are well adapted to be used astwins, so as to cause no friction, as will be readily understood.

Having thus described our invention, we claim- 1. A screw-propellerhaving a spiral co ntinuous blade with no openings therein, making onecomplete revolution, and provided at its outer edge with the spirallaterally-extending flange, for the purpose set forth, the said flangebeing disposed in a plane parallel with the axis of thepropeller,thelength of the said blade being in excess of the diameter of thepropeller, substantially as described.

2. The propeller having the continuous spiral blade formed of separablesectors, the said sectors being separately keyed to the propellershaft,and having their opposing edges secured together, substantially asdescribed.

3. The propeller having the continuous spiral blade forming one completerevolution, the said blade being made of separable sectors, the

said sectors having their opposing edges tongued and grooved, andthereby adapted to effect tight joints, substantially as described.

4. The combination, in a propeller, of the spiral blade and the flange Eat the outer edge of said blade, said flange having the flanges Fembracing the opposite sides of the spiral blade and bolted thereto,substantially as described.

5. The propeller having the continuous spiral blade, forming onecomplete revolution, and the flange Eon the outer edge of the blade, thesaid flange being disposed in a plane parallel With the axis of thepropeller and having its rear edge or projecting portion broader thanits forward projecting portion, for the purpose set forth, substantiallyas described.

In testimony that We claim the foregoing as our own we have heretoafflxed our signatures in presence of two witnesses.

ALEXANDER D. HALL. GEORGE B. SLOAN. -Witnesses to the signature of A. D.Hall:

LEE D. CRAIG, F. F. \VARD. Witnesses to the signature of Geo. B. Sloan:

E. G. SIGGERs, J. H. SIGGERS.

